High resolution morphology and electrical characterization of aged Li-ion battery cathode

Understanding the changes that take place in an aged Lithium-ion (Li-ion) battery cathode is vital to improving battery storage capabilities. High resolution imaging using an atomic force microscope (AFM) and current measurement capabilities are used to determine the difference in surface morphology as well as conductance between unaged and aged cathode. Upon aging, agglomeration of LiFePO4 particles with nanocrystalline deposits is observed and the samples show lower conductance and hence increased resistance. The data identifies potential degradation mechanisms which reduce the conductivity of the cathode leading to poor cycling performance of the battery.

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► Morphological changes help explain the effect of poor conductivity of the aged cathode.
► Possibly loss of carbon and insulating PVDF binder all add to reduced conductivity.
► Increased resistance in the cathode and hence significantly lower conductivity.
► Degradation issues lead to battery capacity reduction ultimately reducing the life of the battery.